/*
 * The org.opensourcephysics.media.core package defines the Open Source Physics
 * media framework for working with video and other media.
 *
 * Copyright (c) 2004  Douglas Brown and Wolfgang Christian.
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston MA 02111-1307 USA
 * or view the license online at http://www.gnu.org/copyleft/gpl.html
 *
 * For additional information and documentation on Open Source Physics,
 * please see <http://www.opensourcephysics.org/>.
 */
package org.opensourcephysics.media.core;

import java.awt.*;
import java.awt.image.*;
import javax.swing.JDialog;

/**
 * This is a Filter that produces a negative version of the source.
 *
 * @author Douglas Brown
 * @version 1.0
 */
public class NegativeFilter extends Filter {

  // instance fields
  private BufferedImage source, input, output;
  private int[] pixels;
  private int w, h;
  private Graphics2D gIn;

  /**
   * Constructs a NegativeFilter object.
   */
  public NegativeFilter() {
  	refresh();
  }

  /**
   * Applies the filter to a source image and returns the result.
   *
   * @param sourceImage the source image
   * @return the filtered image
   */
  public BufferedImage getFilteredImage(BufferedImage sourceImage) {
    if (!isEnabled()) return sourceImage;
    if (sourceImage != source) initialize(sourceImage);
    if (sourceImage != input)
      gIn.drawImage(source, 0, 0, null);
    setOutputToNegative(input);
    return output;
  }

  /**
   * Implements abstract Filter method.
   *
   * @return the inspector
   */
  public JDialog getInspector() {
    return null;
  }

//_____________________________ private methods _______________________

/**
 * Creates the input and output images and ColorConvertOp.
 *
 * @param image a new input image
 */
  private void initialize(BufferedImage image) {
    source = image;
    w = source.getWidth();
    h = source.getHeight();
    pixels = new int[w * h];
    output = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    if (source.getType() == BufferedImage.TYPE_INT_RGB)
      input = source;
    else {
      input = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
      gIn = input.createGraphics();
    }
  }

  /**
   * Sets the output image pixels to the negative of the input pixels.
   *
   * @param image the input image
   */
  private void setOutputToNegative(BufferedImage image) {
    image.getRaster().getDataElements(0, 0, w, h, pixels);
    int pixel, r, g, b;
    for (int i = 0; i < pixels.length; i++) {
      pixel = pixels[i];
      r = 255 - ((pixel >> 16) & 0xff);		// neg red
      g = 255 - ((pixel >>  8) & 0xff);		// neg green
      b = 255 - ((pixel      ) & 0xff);		// neg blue
      pixels[i] = (r << 16) | (g << 8) | b;
    }
    output.getRaster().setDataElements(0, 0, w, h, pixels);
  }

}
